Pub Date : 2025-03-06DOI: 10.1016/j.tws.2025.113139
Zhao-tun An, Hai-lei Kou, Yan Sun, Yan-sheng Wang, Xi-xin Zhang, Jia-qing Lu, Guang-yuan Ma
Suction buckets fabricated from glass fibre-reinforced plastic (GFRP) have emerged as alternatives to conventional steel bucket foundations for offshore wind turbines. Numerical models incorporating a GFRP damage degradation model were developed to investigate the structural response of three critical GFRP bucket sections (S1: top transition, S2: mid-skirt, S3: bottom edge) under ultimate limit states. The results indicate that mechanical changes of the bucket skirt in section S1 are minimized, while the response of section S3 is maximized under different fibre orientations (f) and wall thicknesses (t). The maximum principal stress is minimized for f = 45°. The maximum deformation and ellipticity of the bucket skirt are 27 mm and 0.57 %, respectively, across different fibre orientations. The maximum principal stress and maximum circumferential strain show an obvious decreasing trend as the skirt wall thickness increases. When t ≥ 0.6 %D, the gap between the stresses and strains in each section of the bucket skirt decreases significantly. For varying wall thicknesses of the bucket foundation, the maximum deformation of section S3 are approximately 5.5 times that of sections S1. When the target reliabilities are 3.71, 4.26, and 4.75, the corresponding wall thicknesses of the bucket foundations are 0.259 %D, 0.265 %D, and 0.275 %D.
{"title":"Behavior of GFRP suction bucket in clay under ultimate limit state","authors":"Zhao-tun An, Hai-lei Kou, Yan Sun, Yan-sheng Wang, Xi-xin Zhang, Jia-qing Lu, Guang-yuan Ma","doi":"10.1016/j.tws.2025.113139","DOIUrl":"10.1016/j.tws.2025.113139","url":null,"abstract":"<div><div>Suction buckets fabricated from glass fibre-reinforced plastic (GFRP) have emerged as alternatives to conventional steel bucket foundations for offshore wind turbines. Numerical models incorporating a GFRP damage degradation model were developed to investigate the structural response of three critical GFRP bucket sections (S1: top transition, S2: mid-skirt, S3: bottom edge) under ultimate limit states. The results indicate that mechanical changes of the bucket skirt in section S1 are minimized, while the response of section S3 is maximized under different fibre orientations (<em>f</em>) and wall thicknesses (<em>t</em>). The maximum principal stress is minimized for <em>f</em> = 45°. The maximum deformation and ellipticity of the bucket skirt are 27 mm and 0.57 %, respectively, across different fibre orientations. The maximum principal stress and maximum circumferential strain show an obvious decreasing trend as the skirt wall thickness increases. When <em>t</em> ≥ 0.6 %<em>D</em>, the gap between the stresses and strains in each section of the bucket skirt decreases significantly. For varying wall thicknesses of the bucket foundation, the maximum deformation of section S3 are approximately 5.5 times that of sections S1. When the target reliabilities are 3.71, 4.26, and 4.75, the corresponding wall thicknesses of the bucket foundations are 0.259 %<em>D</em>, 0.265 %<em>D</em>, and 0.275 %<em>D</em>.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113139"},"PeriodicalIF":5.7,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-04DOI: 10.1016/j.tws.2025.113125
L. Simões da Silva , J.O. Gomes Jr. , J.O. Ferreira Filho , H. Carvalho
The Ayrton-Perry approach is the base of the Eurocode 3 design rules for the verification of the buckling resistance of prismatic members, in which different buckling curves associated to different imperfection factors are suggested according to the sections, steel grades, and other parameters. In the revised version of Eurocode 3, the lateral-torsional buckling resistance of simply-supported doubly-symmetric I-section beams is prescribed using a formulation based on the Ayrton-Perry approach and combined with a calibrated generalized imperfection. However, for mono-symmetric I-beams, the General Case predicted in the last version of Eurocode 3 has been maintained, which results in large scatter and an inconsistent design. This paper extends the new Ayrton-Perry approach available in the new version of Eurocode 3 to deal with simply supported mono-symmetric I-section beams under different loading conditions. An advanced numerical model is built and validated to conduct a reliable parametric study in order to assess the available design methodologies and the proposed extended formulation. It is concluded that the proposed formulation exhibits safe-sided results which better agreement with experimental results and advanced numerical simulations, providing more economic and sustainable solutions for mono-symmetric members.
{"title":"Ayrton-Perry approach for the lateral-torsional buckling resistance of mono-symmetric I-section beams","authors":"L. Simões da Silva , J.O. Gomes Jr. , J.O. Ferreira Filho , H. Carvalho","doi":"10.1016/j.tws.2025.113125","DOIUrl":"10.1016/j.tws.2025.113125","url":null,"abstract":"<div><div>The Ayrton-Perry approach is the base of the Eurocode 3 design rules for the verification of the buckling resistance of prismatic members, in which different buckling curves associated to different imperfection factors are suggested according to the sections, steel grades, and other parameters. In the revised version of Eurocode 3, the lateral-torsional buckling resistance of simply-supported doubly-symmetric I-section beams is prescribed using a formulation based on the Ayrton-Perry approach and combined with a calibrated generalized imperfection. However, for mono-symmetric I-beams, the General Case predicted in the last version of Eurocode 3 has been maintained, which results in large scatter and an inconsistent design. This paper extends the new Ayrton-Perry approach available in the new version of Eurocode 3 to deal with simply supported mono-symmetric I-section beams under different loading conditions. An advanced numerical model is built and validated to conduct a reliable parametric study in order to assess the available design methodologies and the proposed extended formulation. It is concluded that the proposed formulation exhibits safe-sided results which better agreement with experimental results and advanced numerical simulations, providing more economic and sustainable solutions for mono-symmetric members.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113125"},"PeriodicalIF":5.7,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-02DOI: 10.1016/j.tws.2025.113089
Zhiqun Guo , Jianming Miao , Zhenfeng Zhai
Segmented arc structures are commonly used in marine engineering but are often vulnerable to wave penetration through their gaps. This study examines the feasibility of adding a low-cost, small breakwater behind a segmented structure to mitigate this issue effectively. An analytical model based on linear potential theory is developed to understand water wave interactions with a cylindrical and segmented arc-shaped dual-layered thin-walled structure. Using eigenfunction matching and separation of variables, the unknown function is expanded within a Chebyshev polynomial framework. With comprehensive boundary condition considerations, the integral equation is transformed into a series of algebraic equations, which are solved to determine the unknown function. Model accuracy is verified by simplifying the model and comparing it with published results. The hydrodynamic response, including wave forces and free surface elevation, is analyzed. Numerical results indicate that a small porous breakwater effectively reduces wave load on the inner cylinder and smooths wave heights within the structure and at the openings, facilitating safe ship passage and operation. This study provides practical guidance and valuable reference for engineering applications.
{"title":"Hydrodynamic characteristics of dual-layered thin-walled concentric segmented structures","authors":"Zhiqun Guo , Jianming Miao , Zhenfeng Zhai","doi":"10.1016/j.tws.2025.113089","DOIUrl":"10.1016/j.tws.2025.113089","url":null,"abstract":"<div><div>Segmented arc structures are commonly used in marine engineering but are often vulnerable to wave penetration through their gaps. This study examines the feasibility of adding a low-cost, small breakwater behind a segmented structure to mitigate this issue effectively. An analytical model based on linear potential theory is developed to understand water wave interactions with a cylindrical and segmented arc-shaped dual-layered thin-walled structure. Using eigenfunction matching and separation of variables, the unknown function is expanded within a Chebyshev polynomial framework. With comprehensive boundary condition considerations, the integral equation is transformed into a series of algebraic equations, which are solved to determine the unknown function. Model accuracy is verified by simplifying the model and comparing it with published results. The hydrodynamic response, including wave forces and free surface elevation, is analyzed. Numerical results indicate that a small porous breakwater effectively reduces wave load on the inner cylinder and smooths wave heights within the structure and at the openings, facilitating safe ship passage and operation. This study provides practical guidance and valuable reference for engineering applications.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113089"},"PeriodicalIF":5.7,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-02DOI: 10.1016/j.tws.2025.113144
Saeed Mirzaei , Mehrdad Hejazi , Reza Ansari
In this paper, the isogeometric analysis (IGA) is extended to study the size-dependent behavior of bending, buckling and free vibration of in-plane bi-directional functionally graded porous microplates with variable thickness. In order to capture the effect of size, the modified strain gradient elasticity theory, which has three length scale parameters, is used. Regarding to the third-order shear deformation theory, the equations of motions are derived by using the Hamilton's principle and then are discretized based on the IGA approach. The material properties vary continuously through in-plane directions by employing the rule of mixture and the porosity distribution is considered an even type. The C2-continuity requirement can be easily achieved by increasing the order of the non-uniform rational B-spline (NURBS) basis functions larger than two. The influences of the size effect, aspect ratios, boundary conditions, thickness variations, material gradations, and porosity distributions on the deflections, the fundamental natural frequencies, and the buckling load values of the rectangular, circular and elliptical microplates are studied. The obtained results are compared with the previously published studies to show the performance and efficiency of the present research.
{"title":"Size-dependent behaviour of in-plane bi-directional functionally graded porous microplates with variable thickness based on the modified strain gradient theory and IGA","authors":"Saeed Mirzaei , Mehrdad Hejazi , Reza Ansari","doi":"10.1016/j.tws.2025.113144","DOIUrl":"10.1016/j.tws.2025.113144","url":null,"abstract":"<div><div>In this paper, the isogeometric analysis (IGA) is extended to study the size-dependent behavior of bending, buckling and free vibration of in-plane bi-directional functionally graded porous microplates with variable thickness. In order to capture the effect of size, the modified strain gradient elasticity theory, which has three length scale parameters, is used. Regarding to the third-order shear deformation theory, the equations of motions are derived by using the Hamilton's principle and then are discretized based on the IGA approach. The material properties vary continuously through in-plane directions by employing the rule of mixture and the porosity distribution is considered an even type. The C<sup>2</sup>-continuity requirement can be easily achieved by increasing the order of the non-uniform rational B-spline (NURBS) basis functions larger than two. The influences of the size effect, aspect ratios, boundary conditions, thickness variations, material gradations, and porosity distributions on the deflections, the fundamental natural frequencies, and the buckling load values of the rectangular, circular and elliptical microplates are studied. The obtained results are compared with the previously published studies to show the performance and efficiency of the present research.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113144"},"PeriodicalIF":5.7,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-02DOI: 10.1016/j.tws.2025.113135
Yanguo Hou , Chenbao Wen , Kuisheng Liu , Jinsong Duan , Haojun Sun , Yanlin Guo
This study investigates the local and global buckling behavior of Transformed Triangular Corrugated Steel Plates (TT-CSP) under bending and shear forces. Theoretical derivations and numerical analyses are employed to establish formulas for the elastic local and global buckling loads. The effects of TT-CSP aspect ratio, fold plate width ratio, TT-CSP thickness, and corrugation folding angle on buckling behavior are examined. A design method for preventing local and global buckling in TT-CSPs is developed based on elastic buckling load and ultimate strength, validated through numerical analyses. The results indicate that the vertical boundaries of TT-CSP do not satisfy the plane assumption, significantly reducing the elastic buckling load and ultimate strength. The width ratio of the main-plate to the sub-plate is identified as the most critical factor affecting the local buckling load. The thickness of TT-CSPs influences shear deformation, with greater thickness leading to a reduction in the local buckling coefficient, whereas corrugation folding angle have a limited impact. Additionally, the limits of the normalized width-to-height ratio for bending are found to be more stringent than those for shear.
{"title":"Local and global buckling prevention design of transformed triangular corrugated plates under shear and bending","authors":"Yanguo Hou , Chenbao Wen , Kuisheng Liu , Jinsong Duan , Haojun Sun , Yanlin Guo","doi":"10.1016/j.tws.2025.113135","DOIUrl":"10.1016/j.tws.2025.113135","url":null,"abstract":"<div><div>This study investigates the local and global buckling behavior of Transformed Triangular Corrugated Steel Plates (TT-CSP) under bending and shear forces. Theoretical derivations and numerical analyses are employed to establish formulas for the elastic local and global buckling loads. The effects of TT-CSP aspect ratio, fold plate width ratio, TT-CSP thickness, and corrugation folding angle on buckling behavior are examined. A design method for preventing local and global buckling in TT-CSPs is developed based on elastic buckling load and ultimate strength, validated through numerical analyses. The results indicate that the vertical boundaries of TT-CSP do not satisfy the plane assumption, significantly reducing the elastic buckling load and ultimate strength. The width ratio of the main-plate to the sub-plate is identified as the most critical factor affecting the local buckling load. The thickness of TT-CSPs influences shear deformation, with greater thickness leading to a reduction in the local buckling coefficient, whereas corrugation folding angle have a limited impact. Additionally, the limits of the normalized width-to-height ratio for bending are found to be more stringent than those for shear.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113135"},"PeriodicalIF":5.7,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.tws.2025.113140
Weiqiang Cai , Liusheng Xiao , Tao Deng , Qijie Hang , Baowei Pan , Jinliang Yuan , Chao Xie
In this study, a trans-scale modeling approach, non-contact high-temperature deformation measurement and flattening compression testing technique are developed and applied for co-sintered thin-layered electrolyte with thick porous electrodes, aiming to comprehensively analyze residual stress and sintering deformation with/without flattening force during/after manufacturing process (including the sintering and flattening process). Coefficient of thermal expansion (CTE) and elastic modulus (E) are first predicted by the Molecular Dynamics method, which together with predicted microscopic volume changes along cell length direction are applied in the finite element modeling for macroscale deformation and residual stress prediction. The results show that the current prediction by the varied CTE and E for sintering deformation is improved by 14 % compared to that using constant ones. The application of a flattening force (31 N, determined from the displacement-compressive force curve) can be effective in reducing cambered deformation (a reduction of 20.14 %), but can also lead to a redistribution of the flattening residual stress within the cell. The stress concentration at the corners of the anode and electrolyte layers is heightened, whereas the flattened residual stress in the electrolyte layer region adjacent to the anode side is diminished. Further identification and optimization of the key parameters relating to the sintering process are conducted which reveals that the sintering temperature has the most significant impact on the sintering displacement, while the larger sintered cambered displacement requires a bigger flattening force to achieve the targeted displacement.
{"title":"Analysis of residual stress for thin-layered electrolyte co-sintered with porous electrodes applied in solid oxide cells","authors":"Weiqiang Cai , Liusheng Xiao , Tao Deng , Qijie Hang , Baowei Pan , Jinliang Yuan , Chao Xie","doi":"10.1016/j.tws.2025.113140","DOIUrl":"10.1016/j.tws.2025.113140","url":null,"abstract":"<div><div>In this study, a trans-scale modeling approach, non-contact high-temperature deformation measurement and flattening compression testing technique are developed and applied for co-sintered thin-layered electrolyte with thick porous electrodes, aiming to comprehensively analyze residual stress and sintering deformation with/without flattening force during/after manufacturing process (including the sintering and flattening process). Coefficient of thermal expansion (CTE) and elastic modulus (<em>E</em>) are first predicted by the Molecular Dynamics method, which together with predicted microscopic volume changes along cell length direction are applied in the finite element modeling for macroscale deformation and residual stress prediction. The results show that the current prediction by the varied CTE and <em>E</em> for sintering deformation is improved by 14 % compared to that using constant ones. The application of a flattening force (31 N, determined from the displacement-compressive force curve) can be effective in reducing cambered deformation (a reduction of 20.14 %), but can also lead to a redistribution of the flattening residual stress within the cell. The stress concentration at the corners of the anode and electrolyte layers is heightened, whereas the flattened residual stress in the electrolyte layer region adjacent to the anode side is diminished. Further identification and optimization of the key parameters relating to the sintering process are conducted which reveals that the sintering temperature has the most significant impact on the sintering displacement, while the larger sintered cambered displacement requires a bigger flattening force to achieve the targeted displacement.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113140"},"PeriodicalIF":5.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-28DOI: 10.1016/j.tws.2025.113108
Maoding Zhou , Yuanhai Zhang , Kui Luo
This study proposes a method for the distortion analysis of thin-walled box girders considering the influence of non-uniform shear deformation of each box-wall slab. Firstly, the distribution pattern of distortion shear flow across the cross-section is derived using the principles of stress equilibrium in micro-elements and the torsional self-balancing condition of the box girder cross-section. Then, by introducing the generalized displacement of shear distortion, according to the deformation continuity and internal force self-balancing conditions of the box girder cross-section, a theoretically sound and practical distribution function for the distortion and warping displacement of thin-walled box girders, accounting for the impact of non-uniform shear deformation is proposed. The governing differential equation for distortion is established through the principle of minimum potential energy. A practical 1D beam-type finite element model for box girder distortion analysis is then proposed, employing the Hermite interpolation function. The reliability and accuracy of this model are verified through a series of numerical examples involving different types of box girders. The results demonstrate that the in-plane and out-of-plane distortion warping stresses of the box-wall slabs, when considering non-uniform shear deformation, align well with measured values and three-dimensional finite element results. Notably, shear deformation significantly impacts the distortion effect of the top flange in box girders. Ignoring the influence of non-uniform shear deformation may lead to an underestimating the distortion warping stresses at critical cross-sections of box girder bridges. The research findings provide an effective means for the improved analysis of box girder distortion.
{"title":"Distortion warping displacement pattern of thin-walled box girders under the influence of non-uniform shear deformation and its corresponding beam-type finite element model","authors":"Maoding Zhou , Yuanhai Zhang , Kui Luo","doi":"10.1016/j.tws.2025.113108","DOIUrl":"10.1016/j.tws.2025.113108","url":null,"abstract":"<div><div>This study proposes a method for the distortion analysis of thin-walled box girders considering the influence of non-uniform shear deformation of each box-wall slab. Firstly, the distribution pattern of distortion shear flow across the cross-section is derived using the principles of stress equilibrium in micro-elements and the torsional self-balancing condition of the box girder cross-section. Then, by introducing the generalized displacement of shear distortion, according to the deformation continuity and internal force self-balancing conditions of the box girder cross-section, a theoretically sound and practical distribution function for the distortion and warping displacement of thin-walled box girders, accounting for the impact of non-uniform shear deformation is proposed. The governing differential equation for distortion is established through the principle of minimum potential energy. A practical 1D beam-type finite element model for box girder distortion analysis is then proposed, employing the Hermite interpolation function. The reliability and accuracy of this model are verified through a series of numerical examples involving different types of box girders. The results demonstrate that the in-plane and out-of-plane distortion warping stresses of the box-wall slabs, when considering non-uniform shear deformation, align well with measured values and three-dimensional finite element results. Notably, shear deformation significantly impacts the distortion effect of the top flange in box girders. Ignoring the influence of non-uniform shear deformation may lead to an underestimating the distortion warping stresses at critical cross-sections of box girder bridges. The research findings provide an effective means for the improved analysis of box girder distortion.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113108"},"PeriodicalIF":5.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-28DOI: 10.1016/j.tws.2025.113101
Rodrigo Gonçalves
This paper extends the first-order Generalized Beam Theory (GBT) formulation for tapered regular convex polygonal tubes, recently developed by the author (Gonçalves, 2025), to the buckling (linear stability analysis) case. The proposed extension allows calculating global-distortional-local bifurcation loads and buckling modes with great accuracy and a very low computational cost, even for high taper angles, due to the fact that it inherits the key features of its first-order counterpart: (i) it uses the GBT deformation modes of the prismatic case, which have a clear physical meaning, (ii) no additional simplifications are introduced, even though the member is genuinely tapered, and (iii) the optional membrane strain assumptions of the prismatic GBT are satisfied exactly. Naturally, the proposed extension retains the unique GBT modal decomposition features, which allow a straightforward classification of the buckling mode nature (global, distortional and local). Even though the proposed formulation is necessarily complex, due to the tapered geometry, all expressions required to implement a suitable displacement-based finite element are provided in a simple vector–matrix format. The computational efficiency of the element is shown in several numerical examples, where results obtained with refined shell finite element meshes are reported for comparison purposes.
{"title":"Extension of GBT to the buckling analysis of tapered regular convex polygonal tubes","authors":"Rodrigo Gonçalves","doi":"10.1016/j.tws.2025.113101","DOIUrl":"10.1016/j.tws.2025.113101","url":null,"abstract":"<div><div>This paper extends the first-order Generalized Beam Theory (GBT) formulation for tapered regular convex polygonal tubes, recently developed by the author (Gonçalves, 2025), to the buckling (linear stability analysis) case. The proposed extension allows calculating global-distortional-local bifurcation loads and buckling modes with great accuracy and a very low computational cost, even for high taper angles, due to the fact that it inherits the key features of its first-order counterpart: (i) it uses the GBT deformation modes of the prismatic case, which have a clear physical meaning, (ii) no additional simplifications are introduced, even though the member is genuinely tapered, and (iii) the optional membrane strain assumptions of the prismatic GBT are satisfied exactly. Naturally, the proposed extension retains the unique GBT modal decomposition features, which allow a straightforward classification of the buckling mode nature (global, distortional and local). Even though the proposed formulation is necessarily complex, due to the tapered geometry, all expressions required to implement a suitable displacement-based finite element are provided in a simple vector–matrix format. The computational efficiency of the element is shown in several numerical examples, where results obtained with refined shell finite element meshes are reported for comparison purposes.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113101"},"PeriodicalIF":5.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-27DOI: 10.1016/j.tws.2025.113131
Ruixin Wang , Chaoyue Chen , Tingwei Cao , Ruixin Zhao , Yuyang Hou , Songzhe Xu , Tao Hu , Xia Li , Wenjun Zhao , Gang Ji , Ninshu Ma , Jiang Wang , Zhongming Ren
Thermal distortion and residual stress are major issues affecting dimensional accuracy and mechanical properties in laser additive manufacturing (LAM). This study investigates the evolution of thermal distortion and the formation mechanism of residual stress in Ti-6Al-4V alloy during laser-directed energy deposition (L-DED). An in-situ monitoring system recorded the distortion and temperature histories of the sample during deposition. Residual stress in various regions and directions of the final thin-wall was analyzed using the contour method and XRD. The results show that during each layer deposition, the interaction between tensile and compressive stresses causes the free end of the substrate to initially bend downward and subsequently upward. Different linear energy densities (El) lead to varying distortion modes of the substrate. For El values between 75 and 150 J/mm, substrate distortion height increases with deposition layers. For El values between 150 and 300 J/mm, it first increases and then decreases. By combining in-situ monitoring data with residual stress results, this study clarifies the evolution of thermal distortion, the mechanism of residual stress formation, and their relationship during l-DED. Samples with greater distortion tend to exhibit lower residual stress. The distortion of Ehigh samples is 0.73 mm greater than that of Elow samples, yet their maximum residual stress is 82.8 MPa lower. The higher cooling rate in the deposition region creates local tensile stress, while compressive stress forms in the surrounding region. As deposition progresses, the region of maximum tensile stress shifts upward along the building direction until complete. This study provides new insights into the evolution of thermal distortion and the mechanisms of residual stress formation in LAM, contributing to the control and reduction of residual stress.
{"title":"Thermal distortion evolution and residual stress characteristics of Ti-6Al-4 V alloy by laser-directed energy deposition: In-situ monitoring, contour method, and XRD","authors":"Ruixin Wang , Chaoyue Chen , Tingwei Cao , Ruixin Zhao , Yuyang Hou , Songzhe Xu , Tao Hu , Xia Li , Wenjun Zhao , Gang Ji , Ninshu Ma , Jiang Wang , Zhongming Ren","doi":"10.1016/j.tws.2025.113131","DOIUrl":"10.1016/j.tws.2025.113131","url":null,"abstract":"<div><div>Thermal distortion and residual stress are major issues affecting dimensional accuracy and mechanical properties in laser additive manufacturing (LAM). This study investigates the evolution of thermal distortion and the formation mechanism of residual stress in Ti-6Al-4V alloy during laser-directed energy deposition (L-DED). An in-situ monitoring system recorded the distortion and temperature histories of the sample during deposition. Residual stress in various regions and directions of the final thin-wall was analyzed using the contour method and XRD. The results show that during each layer deposition, the interaction between tensile and compressive stresses causes the free end of the substrate to initially bend downward and subsequently upward. Different linear energy densities (<em>E<sub>l</sub></em>) lead to varying distortion modes of the substrate. For <em>E<sub>l</sub></em> values between 75 and 150 J/mm, substrate distortion height increases with deposition layers. For <em>E<sub>l</sub></em> values between 150 and 300 J/mm, it first increases and then decreases. By combining in-situ monitoring data with residual stress results, this study clarifies the evolution of thermal distortion, the mechanism of residual stress formation, and their relationship during l-DED. Samples with greater distortion tend to exhibit lower residual stress. The distortion of <em>E<sub>high</sub></em> samples is 0.73 mm greater than that of <em>E<sub>low</sub></em> samples, yet their maximum residual stress is 82.8 MPa lower. The higher cooling rate in the deposition region creates local tensile stress, while compressive stress forms in the surrounding region. As deposition progresses, the region of maximum tensile stress shifts upward along the building direction until complete. This study provides new insights into the evolution of thermal distortion and the mechanisms of residual stress formation in LAM, contributing to the control and reduction of residual stress.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113131"},"PeriodicalIF":5.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-27DOI: 10.1016/j.tws.2025.113130
Xiao-Yi Qiu , Xu-Hong Zhou , Shan Gao , Bin Wang , Wei Ren , Yu-Hang Wang
Under the coupling effect of wind load and wave load, the corner columns of the offshore wind turbine concrete-filled steel tube(CFST) jacket structure will undergo cyclic tension and compression. The alteration of concrete crack surface contact and the support provided by the filled concrete to the steel tube have resulted in the absence of a precise model capable of accurately describing the behavior of CFST columns under cyclic tensile-compressive loads with different loading paths. Therefore, cyclic tensile-compressive load tests were conducted on a total of 9 specimens under 5 different loading schemes, considering the effects of load amplitude, load level, and number of cycles. The failure modes of the specimens under cyclic tensile-compressive loads were obtained. Analysis of the experimental results revealed that the ultimate capacity and ductility are slightly influenced by the loading schemes. The ultimate capacity is positively correlated with the load level, whereas ductility exhibits a negative correlation with the load level, with ductility being more significantly affected. Additionally, the compressive stiffness of the specimens is notably influenced by the loading schemes; higher load levels result in more pronounced stiffness degradation, with compression having a greater impact than tension. Finally, several existing methods were adopted to predict the ultimate compressive and tensile capacity. The results showed the measured tensile ultimate capacity aligns closely with the measured results, whereas the compressive ultimate capacities are consistently underestimated.
{"title":"Experimental study on cyclic tensile-compressive behavior of concrete-filled steel tube column for offshore wind turbine jacket structure","authors":"Xiao-Yi Qiu , Xu-Hong Zhou , Shan Gao , Bin Wang , Wei Ren , Yu-Hang Wang","doi":"10.1016/j.tws.2025.113130","DOIUrl":"10.1016/j.tws.2025.113130","url":null,"abstract":"<div><div>Under the coupling effect of wind load and wave load, the corner columns of the offshore wind turbine concrete-filled steel tube(CFST) jacket structure will undergo cyclic tension and compression. The alteration of concrete crack surface contact and the support provided by the filled concrete to the steel tube have resulted in the absence of a precise model capable of accurately describing the behavior of CFST columns under cyclic tensile-compressive loads with different loading paths. Therefore, cyclic tensile-compressive load tests were conducted on a total of 9 specimens under 5 different loading schemes, considering the effects of load amplitude, load level, and number of cycles. The failure modes of the specimens under cyclic tensile-compressive loads were obtained. Analysis of the experimental results revealed that the ultimate capacity and ductility are slightly influenced by the loading schemes. The ultimate capacity is positively correlated with the load level, whereas ductility exhibits a negative correlation with the load level, with ductility being more significantly affected. Additionally, the compressive stiffness of the specimens is notably influenced by the loading schemes; higher load levels result in more pronounced stiffness degradation, with compression having a greater impact than tension. Finally, several existing methods were adopted to predict the ultimate compressive and tensile capacity. The results showed the measured tensile ultimate capacity aligns closely with the measured results, whereas the compressive ultimate capacities are consistently underestimated.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113130"},"PeriodicalIF":5.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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